This message may seem a bit basic for most but I would like some guidance. I recently became an owner of a 1968 350 HO firebird. All numbers match except that the carburetor is not original. The car is in great shape but not a show car and will not be used for a daily drive. The car has a Holley double pumper carb on it now. I was considering changing it out to the proper quadrajet to adhere to the originality of the car. The mechanic that is working on the car said that I would get much better mileage with a quadrajet and for that reason he suggested a change. I am not sure the benefit(s) of the Holley double pumper (two barrel) vs the quadrajet as far as desirabality for resale and driving performance and if it worth spending the money. Would appreciate your thoughts. Thanks